Area Forecast Discussion
Issued by NWS Grand Junction, CO
Issued by NWS Grand Junction, CO
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313 FXUS65 KGJT 212327 AFDGJT Area Forecast Discussion National Weather Service Grand Junction CO 527 PM MDT Tue May 21 2024 .KEY MESSAGES... - Scattered showers and thunderstorms continue through this evening before tapering off overnight. Low temperatures will be much cooler than normal. - Warmer and drier weather returns on Wednesday with highs roughly 10 degrees warmer than today. - Mainly dry weather continues through the end of the week before more unsettled weather returns this weekend. && .SHORT TERM /THROUGH WEDNESDAY NIGHT/... Issued at 311 PM MDT Tue May 21 2024 GOES-East satellite imagery continues to show a compact shortwave trough rotating across eastern Utah and western Colorado this afternoon. Combined with residual moisture and daytime heating, large scale forcing for ascent is producing scattered showers and a few thunderstorms... mainly across the higher terrain along the Continental Divide mountains and portions of northeast Utah and northwest Colorado. Despite weak instability, fairly steep lapse rates are resulting in small but vigorous precipitation cores with moderate to briefly heavy rainfall rates. At or above 9000 to 10000 feet, this is also leading to snowfall rates of the same intensity across the Continental Divide mountains. Given the time of year however, snowfall accumulations are not affecting road surfaces, with webcams only showing wet roads on all of our major high mountain passes. Otherwise, the trough and last night`s cold front have brought in a much cooler air mass, which is resulting in high temperatures well below climatological norms. The trough will exit the region to the east tonight, taking the remaining showers along with it. Clearing skies and light winds along with the unseasonably cool air mass overhead will lead to a pretty chilly night for late May standards, with temperatures nearing or dropping below the freezing point for many locations in the higher elevations. Those with agricultural interests or sensitive vegetation will want to keep an eye on temperatures tonight into early Wednesday morning. After a cool start, temperatures will quickly rebound on Wednesday as flow becomes southwesterly once again. High temperatures will still be near to slightly below normal, but much warmer than today. Mostly sunny skies will be the rule, though a few more clouds may bubble up across the high elevations along the Continental Divide. Can`t completely rule out a pop-up shower or two there either, but overall the day will be mainly if not completely dry. Another cold front is progged to approach northeast Utah late Wednesday night and will be on the doorstep right around daybreak Thursday morning. Other than that, the rest of the night will be quiet with lows roughly 5 to 15 degrees warmer than tonight. && .LONG TERM /THURSDAY THROUGH TUESDAY/... Issued at 311 PM MDT Tue May 21 2024 The wave train keeps rolling on Thursday as the next mid-level trough moves across the northern Rockies. This system will drive a cold front across the area which, when combined with decent mid and upper level forcing, brings a good chance for showers/thunderstorms with northwest Colorado and the northern Colorado mountains favored. Flow aloft becomes west- southwesterly in the wake of this system on Friday, though residual moisture, instability and modest jet divergence is expected to be sufficient to generate isolated to scattered moist convection over the Colorado mountains, mainly during the afternoon and evening period. The next trough to impact the region arrives Saturday resulting in more widespread shower and thunderstorm activity along with light snow in the higher elevations. On Sunday a closed low over the northern Intermountain region pushes eastward just brushing northern Colorado keeping showers going over the northern and central mountains, northwest Colorado plateau, and the I-70 corridor east of Grand Junction. Expect a ridge to build over the Rockies Monday into Tuesday, though it`s likely modest residual moisture will fuel a handful of afternoon showers/thunderstorms along the Continental Divide each afternoon. Temperatures during this unsettled period will be near or a little below seasonal norms from Thursday through the weekend before a warming trend begins Monday into Tuesday. && .AVIATION /00Z TAFS THROUGH 00Z THURSDAY/... Issued at 523 PM MDT Tue May 21 2024 Scattered showers and thunderstorms will continue to move across the area this evening before finally dissipating after sunset. These showers are capable of producing gusty winds, small hail, brief heavy rain or, at higher elevations, snow, and lightning. Brief reductions to MVFR/IFR conditions are possible with any shower moving over a terminal. KASE, KEGE, and KRIL will flirt with ILS breakpoints through 06z. After activity comes to an end, VFR conditions will prevail for the remainder of the period, with rapidly clearing skies. Winds will lighten overnight and follow typical terrain-driven patterns. Look for the return of gusty southwest to westerly winds tomorrow afternoon. && .GJT WATCHES/WARNINGS/ADVISORIES... CO...None. UT...None. && $$ SHORT TERM...MDM LONG TERM...NL AVIATION...TGJT